RESUMO
The centrosymmetric crystal structure of the novel semi-organic compound, 3C(3)H(5)N(2)S(+)·HSO(4) (-)·SO(4) (2-)·H(2)O, is based on chains of alternating anions and water mol-ecules (formed by O-Hâ¯O hydrogen bonds). The chains are inter-connected with the 2-amino-1,3-thia-zolium cations via strong N-Hâ¯O and weak C-Hâ¯O hydrogen-bonding inter-actions into a three-dimensional network.
RESUMO
In the title compound, C(3)H(5)N(2)S(+)·H(2)PO(4) (-), the dihydrogen phosphate anions form infinite chains along [001] via short O-Hâ¯O hydrogen bonds. The 2-amino-thia-zolium cations inter-connect these chains into a three-dimensional network by short linear or bifurcated N-Hâ¯O and weak C-Hâ¯O hydrogen bonds.
RESUMO
Large-scale plasma was created in gas mixtures containing carbon monoxide by high-power laser-induced dielectric breakdown (LIDB). The composition of the mixtures used corresponded to a cometary and/or meteoritic impact into the Earth's early atmosphere. A multiple-centimeter-sized fireball was created by focusing a single 85 J, 450 ps near-infrared laser pulse into the center of a 15 L gas cell. The excited reaction intermediates that formed in various stages of the LIDB plasma chemical evolution were investigated by optical emission spectroscopy (OES) with temporal resolution. Special attention was paid to any OES signs of molecular ions. However, carbon monoxide cations were registered only if their production was enhanced by Penning ionization, i.e., excess He was added to the CO. The chemical consequences of laser-produced plasma generation in a CO-N 2-H 2O mixture were investigated using high resolution Fourier-transform infrared absorption spectroscopy (FTIR) and gas chromatography (GC). Several simple inorganic and organic compounds were identified in the reaction mixture exposed to ten laser sparks. H 2 (18)O was used to avoid possible contamination. The large laser spark triggered more complex reactivity originating in carbon monoxide than expected, when taking into account the strong triple bond of carbon monoxide causing typically inefficient dissociation of this molecule in electrical discharges.
RESUMO
A large-scale, double-stream gas puff target has been illuminated by sub-kJ, near-infrared (NIR) focused laser pulses at the PALS facility (Prague Asterix Laser System) to produce high-energy pulses of soft X rays from hot, dense plasma. The double-puff arrangement ensures high gas density and conversion efficiency from NIR to X rays approaching that typical for solid targets. In addition, its major advantage over solid targets is that it is free of debris and has substantially suppressed charged-particle emission. The X-ray emission characteristics of the source were determined for a range of gases that included krypton, xenon, N(2), CO and N(2)-CO. A demonstrated application of the xenon-based source is a single-shot damage induction to plasmid DNA. The yields of single-strand breaks (SSBs) and double-strand breaks (DSBs) were determined as a function of energy fluence adjusted by varying distance of sample from the source and thickness of aluminum filters.
Assuntos
Dano ao DNA/efeitos da radiação , Lasers , Plasmídeos/química , Radiobiologia/instrumentação , Pesquisa/instrumentação , Manejo de Espécimes/instrumentação , Raios X , Desenho de Equipamento , Análise de Falha de Equipamento , Nanotecnologia/instrumentação , Nanotecnologia/métodos , Plasmídeos/efeitos da radiação , Doses de Radiação , Radiobiologia/métodos , Projetos de Pesquisa , Manejo de Espécimes/métodosRESUMO
We report on an electrochemical conversion of N2 to NH3 at ambient pressure and 60 degrees C, which is mediated by reduced C(60) inside the molecular cavity of gamma-cyclodextrin.
RESUMO
Large-scale plasma was created in molecular gases (CO, CO2, N2, H2O) and their mixtures by high-power laser-induced dielectric breakdown (LIDB). Compositions of the mixtures used are those suggested for the early earth's atmosphere of neutral and/or mildly reducing character. Time-integrated optical spectra emitted from the laser spark have been measured and analyzed. The spectra of the plasma generated in the CO-containing mixtures are dominated by emission of both C2 and CN radicals. A vibrational temperature of approximately 10(4) K was determined according to an intensity distribution in a vibronic structure of the CN (B2Sigma(+)u-X2Sigma(+)g) violet band. For comparison, the NH3-CH4-H2-H2O mixture has been irradiated as a model of the strongly reducing version of the early earth's atmosphere. In this mixture, excited CN seems to be significantly less abundant than C2. The LIDB experiments were in the molecular gases carried out not only in the static cell but also using a large, double stream pulse jet (gas puff target) placed in the vacuum interaction chamber. The obtained soft X-ray emission spectra indicate the presence of highly charged atomic ions in the hot core of high-power laser sparks.